The present invention relates to electric plugs for extension cables or the like, and more particularly to such an electric plug, which is easy to assemble, and durable in use.
A variety of electric plugs have been disclosed for use with an extension cable for electric home appliances and computers. FIG. 1 illustrates an electric plug according to the prior art. This structure of electric plug comprises a hollow housing, a blade holder shell fitted into the housing, the housing having a locating hole on the front side wall thereof in the middle and two insertion holes spaced from the locating hole at two opposite lateral sides, two electric wire respectively installed in the housing, two metal blades respectively mounted in the blade holder shell and connected to the electric wires and extended out of the insertion holes on the front side wall of the housing, and a cartridge fuse connected between one electric wire and one metal blade. One electric wire is connected to the corresponding metal blade by welding. This structure of electric plug has drawbacks. One drawback of this structure of electric plug is its complicated assembly procedure. Another drawback of this structure is the application of welding to fasten one electric wire to the corresponding metal blade. During welding, a toxic gas will be produced, causing air pollution. Further, in order to hold the metal blades firmly in the insertion holes on the front side wall of the housing, the size of the insertion holes must not greater than the metal blades. Because the size of the insertion holes is not greater than the metal blades, it is not easy to accurately insert the metal blades through the insertion holes when inserting the blade holder shell into the housing, and the metal blades tend to be deformed during the assembly process of the electric plug.
The invention has been accomplished to provide an electric plug, which eliminates the aforesaid drawbacks. According to one aspect of the present invention, the electric plug comprises a hollow housing having a front opening and a rear opening, and a blade holder shell fitted into the housing to hold two electric wires and two metal blade, a fuse connected between one electric wire and one metal blade, wherein the blade holder shell has a vertical rear side wall press-fitted into the rear opening of the housing, and a front protruding block fitted into the front opening of the housing to hold down the metal blades, keeping the metal blades squeezed in between two side walls of the front opening of the housing and two opposite lateral sides of the protruding block of the blade holder shell. According to another aspect of the present invention, one electric wire has a metal conductor clamp fixedly mounted on one end thereof and hooked in a retaining hole on the corresponding metal blade.